Ultrasonic diagnostic apparatus and image processing apparatus

ABSTRACT

In an ultrasonic diagnostic apparatus according to an embodiment, a separator separates an arbitrary region of a displayed object represented from image data, in a depth direction, based on a characterizing quantity included in the image data. An image generation controller generates an image to be displayed in which depth direction information is reflected on the arbitrary region of the displayed object, separated by the separator. A display controller causes a monitor being capable of providing a stereoscopic vision to display the image to be displayed generated by the image generation controller.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of International Application No.PCT/JP2012/061899, filed on May 9, 2012 which claims the benefit ofpriority of the prior Japanese Patent Application No. 2011-115935, filedon May 24, 2011, the entire contents of which are incorporated herein byreference.

FIELD

Embodiments described herein relate generally to an ultrasonicdiagnostic apparatus and an image processing apparatus.

BACKGROUND

Ultrasonic diagnostic apparatuses have been conventionally used inmedical care today in examining or diagnosing various types of bodytissues such as those of a heart, a liver, a kidney, and a mammarygland. Ultrasonic diagnostic apparatuses has advantages over othermedical image diagnostic apparatuses, such as X-ray diagnosticapparatuses and X-ray computed tomographic imaging apparatuses, in thatthey are easier to use and non-intrusive to subjects without the risk ofradiation exposure, for example.

Such an ultrasonic diagnostic apparatus generates and displays atomographic image (B-mode image) of a tissue structure in a subject bytransmitting ultrasound waves from an ultrasound probe, and receivingreflection wave signals reflected on the internal tissues of thesubject. A more recent ultrasonic diagnostic apparatus generates anddisplays a color Doppler image presenting blood flow information such asthe velocity, turbulence, and power of blood flows in a distinguishablemanner by colors, by taking advantage of the Doppler shift of ultrasonicwaves, as well as a region where the blood flows are present within asubject. There have been situations where visibility of an imagecaptured by such an ultrasonic diagnostic apparatus is degraded.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of an example of an overall structure of anultrasonic diagnostic apparatus according to a first embodiment;

FIG. 2A is a schematic for explaining an example of a stereoscopicdisplay monitor providing a stereoscopic vision using two-parallaximages;

FIG. 2B is a schematic for explaining an example of a stereoscopicdisplay monitor providing a stereoscopic vision using two-parallaximages;

FIG. 3 is a schematic for explaining an example of a stereoscopicdisplay monitor providing a stereoscopic vision using nine-parallaximages;

FIG. 4 is a schematic for explaining an example of a volume renderingprocess performed by an image generator in the first embodiment;

FIG. 5 is a schematic for explaining an example of an issue to beaddressed in the first embodiment;

FIG. 6 is a schematic of an example of a configuration of a controllerin the first embodiment;

FIG. 7A is a schematic for explaining an example of a process performedby a separator in the first embodiment;

FIG. 7B is a schematic for explaining the example of the processperformed by the separator in the first embodiment;

FIG. 8 is a schematic for explaining an example performed by an imagegeneration controller in the first embodiment;

FIG. 9 is a schematic for explaining an example of a process performedby a depth setting module in the first embodiment; and

FIG. 10 is a flowchart illustrating a process performed by theultrasonic diagnostic apparatus in the first embodiment.

DETAILED DESCRIPTION

According to an embodiment, an ultrasonic diagnostic apparatus includesa separator, an image generator and a display controller. The separatorconfigured to separate an arbitrary region of a displayed objectrepresented from image data, in a depth direction, based on acharacterizing quantity included in the image data. The image generatorconfigured to generate an image to be displayed in which information ofthe depth direction is reflected on the arbitrary region of thedisplayed object, the region being separated by the separator. Thedisplay controller configured to cause a display unit being capable ofproviding a stereoscopic vision to display the image to be displayedgenerated by the image generator.

An ultrasonic diagnostic apparatus and an image processing apparatusaccording to an embodiment will be explained in detail with reference tothe accompanying drawings. To begin with, terms used in the embodimentbelow will be explained. A “parallax image group” is a group of imagesgenerated by applying a volume rendering process to volume data whileshifting viewpoint positions by a given parallax angle. In other words,a “parallax image group” includes a plurality of “parallax images” eachof which has a different “viewpoint position”. A “parallax angle” is anangle determined by adjacent viewpoint positions among viewpointpositions specified for generation of the “parallax image group” and agiven position in a space represented by the volume data (e.g., thecenter of the space). A “parallax number” is the number of “parallaximages” required for a stereoscopic vision on a stereoscopic displaymonitor. A “nine-parallax image” mentioned below means a “parallax imagegroup” with nine “parallax images”. A “two-parallax image” mentionedbelow means a “parallax image group” with two “parallax images”. A“stereoscopic image” mentioned below is a three-dimensional imageobserved by an observer when a parallax image group is output anddisplayed by a display unit being capable of providing a stereoscopicvision.

First Embodiment

An overall structure of an ultrasonic diagnostic apparatus according toa first embodiment will be explained with reference to FIG. 1. FIG. 1 isa schematic of an example of an overall structure of an ultrasonicdiagnostic apparatus 1 according to the first embodiment. As illustratedin FIG. 1, the ultrasonic diagnostic apparatus 1 according to the firstembodiment includes an ultrasound probe 11, an input device 12, amonitor 13, and a main apparatus 100.

The ultrasound probe 11 includes a plurality of piezoelectric vibrators.The piezoelectric vibrators generate ultrasonic waves based on drivingsignals supplied by a transmitter-receiver 110 provided in the mainapparatus 100, which is to be explained later, and receives reflectionwaves from a subject P and converts the reflection waves into electricalsignals. The ultrasound probe 11 also includes matching layers providedon the piezoelectric vibrators, and a backing material for preventingthe ultrasonic waves from propagating backwardly from the piezoelectricvibrators.

When an ultrasonic wave is transmitted from the ultrasound probe 11toward the subject P, the ultrasonic wave thus transmitted is reflectedone after another on a discontinuous acoustic impedance surface in bodytissues within the subject P, and received as reflection wave signals bythe piezoelectric vibrators in the ultrasound probe 11. The amplitude ofthe reflection wave signals thus received depends on an acousticimpedance difference on the discontinuous surface on which theultrasonic wave is reflected. When a transmitted ultrasonic wave pulseis reflected on the surface of a moving blood flow or of a cardiac wall,the frequency of the reflection wave signal thus received is shifted bythe Doppler shift depending on the velocity component of the moving bodywith respect to the direction in which the ultrasonic wave istransmitted.

The embodiment is applicable to both cases where the subject P isscanned two-dimensionally using an ultrasound probe 11 being aone-dimensional ultrasound probe in which a plurality of piezoelectricvibrators are arranged in a line, and where the subject P is scannedthree-dimensionally using an ultrasound probe 11 in which a plurality ofpiezoelectric vibrators included in a one-dimensional ultrasound probeare mechanically swung or using an ultrasound probe 11 being atwo-dimensional ultrasound probe having a plurality of piezoelectricvibrators arranged two-dimensionally in a grid.

The input device 12 includes a mouse, a keyboard, a button, a panelswitch, a touch command screen, a foot switch, and a track ball, forexample. The input device 12 receives various setting requests from anoperator of the ultrasonic diagnostic apparatus 1, and forwards thevarious setting requests thus received to the main apparatus 100. Forexample, the input device 12 receives an input operation for setting thedepth of a stereoscopic image.

The monitor 13 displays a graphical user interface (GUI) for allowingthe operator of the ultrasonic diagnostic apparatus 1 to input varioussetting requests using the input device 12, and an ultrasound imagegenerated by the main apparatus 100, for example.

The monitor 13 is a monitor enabled for a stereoscopic vision(hereinafter, referred to as a stereoscopic display monitor), anddisplays various types of information. For example, the monitor 13displays a parallax image group generated by the main apparatus 100, anda GUI for receiving various instructions from an operator.

The stereoscopic display monitor will now be explained. A common,general-purpose monitor that is most widely used today displaystwo-dimensional images two-dimensionally, and is not capable ofdisplaying a two-dimensional image stereoscopically. If an observerwishes for a stereoscopic vision on the general-purpose monitor, anapparatus outputting images to the general-purpose monitor needs todisplay two-parallax images in parallel that can be perceived by theobserver stereoscopically, using a parallel technique or a crossed-eyetechnique. Alternatively, the apparatus outputting images to thegeneral-purpose monitor needs to present images that can be perceivedstereoscopically by the observer using anaglyph, which uses a pair ofglasses having a red filter for the left eye and a blue filter for theright eye, for example.

Furthermore, some stereoscopic display monitors enable two-parallaximages (also referred to as binocular parallax images) to be perceivedstereoscopically using special equipment such as a pair of stereoscopicglasses.

FIGS. 2A and 2B are schematics for explaining an example of astereoscopic display monitor providing a stereoscopic vision usingtwo-parallax images. The example illustrated in FIGS. 2A and 2Brepresents a stereoscopic display monitor providing a stereoscopicvision using a shutter technique. In this example, a pair of shutterglasses are used as stereoscopic glasses worn by an observer whoobserves the monitor. The stereoscopic display monitor outputstwo-parallax images onto the monitor alternatingly. For example, themonitor illustrated in FIG. 2A outputs an image for the left eye and animage for the right eye alternatingly at 120 hertz. An infrared emitteris installed in the monitor, as illustrated in FIG. 2A, and the infraredemitter controls infrared outputs based on the timing at which theimages are swapped.

The infrared output from the infrared emitter is received by an infraredreceiver provided on the shutter glasses illustrated in FIG. 2A. Ashutter is installed on the frame on each side of the shutter glasses.The shutter glasses switch the right shutter and the left shutterbetween a transmissive state and a light-blocking state alternatinglybased on the timing at which the infrared receiver receives infrared. Aprocess of switching the shutters between the transmissive state and thelight-blocking state will now be explained.

As illustrated in FIG. 2B, each of the shutters includes an incomingpolarizer and an outgoing polarizer, and also includes a liquid crystallayer interposed between the incoming polarizer and the outgoingpolarizer. The incoming polarizer and the outgoing polarizer areorthogonal to each other, as illustrated in FIG. 2B. In an “OFF” stateduring which a voltage is not applied as illustrated in FIG. 2B, thelight having passed through the incoming polarizer is rotated by 90degrees by the effect of the liquid crystal layer, and thus passesthrough the outgoing polarizer. In other words, a shutter with novoltage applied is in the transmissive state.

By contrast, as illustrated in FIG. 2B, in an “ON” state during which avoltage is applied, the polarization rotation effect of liquid crystalmolecules in the liquid crystal layer is lost. Therefore, the lighthaving passed through the incoming polarizer is blocked by the outgoingpolarizer. In other words, the shutter applied with a voltage is in thelight-blocking state.

The infrared emitter outputs infrared for a time period while which animage for the left eye is displayed on the monitor, for example. Duringthe time the infrared receiver is receiving infrared, no voltage isapplied to the shutter for the left eye, while a voltage is applied tothe shutter for the right eye. In this manner, as illustrated in FIG.2A, the shutter for the right eye is in the light-blocking state and theshutter for the left eye is in the transmissive state to cause the imagefor the left eye to enter the left eye of the observer. For a timeperiod while which an image for the right eye is displayed on themonitor, the infrared emitter stops outputting infrared. When theinfrared receiver receives no infrared, a voltage is applied to theshutter for the left eye, while no voltage is applied to the shutter forthe right eye. In this manner, the shutter for the left eye is in thelight-blocking state, and the shutter for the right eye is in thetransmissive state to cause the image for the right eye to enter theright eye of the observer. As explained above, the stereoscopic displaymonitor illustrated in FIGS. 2A and 2B makes a display that can bestereoscopically perceived by the observer, by switching the states ofthe shutters in association with the images displayed on the monitor.Also known as a stereoscopic display monitor being capable of displayingtwo-parallax images stereoscopically is a monitor for which a pair ofpolarized glasses are used, in addition to the shutter techniqueexplained above.

Some stereoscopic display monitors that have recently been put intopractical use allow multiple-parallax images, e.g., nine-parallaximages, to be stereoscopically viewed by an observer with the nakedeyes, by adopting a light ray controller such as a lenticular lens. Sucha stereoscopic display monitor enables stereoscopy using the binocularparallax, and also enables stereoscopy using moving parallax, where avideo observed by an observer changes following the movement of theobserver's viewpoint.

FIG. 3 is a schematic for explaining an example of a stereoscopicdisplay monitor providing a stereoscopic vision using nine-parallaximages. In the stereoscopic display monitor illustrated in FIG. 3, alight ray controller is arranged on the front surface of a flat displayscreen 200 such as a liquid crystal panel. For example, in thestereoscopic display monitor illustrated in FIG. 3, a verticallenticular sheet 201 having an optical aperture extending in a verticaldirection is fitted on the front surface of the display screen 200 as alight ray controller. Although the vertical lenticular sheet 201 isfitted so that the convex of the vertical lenticular sheet 201 faces thefront side in the example illustrated in FIG. 3, the vertical lenticularsheet 201 may be also fitted so that the convex faces the display screen200.

As illustrated in FIG. 3, the display screen 200 has pixels 202 that arearranged in a matrix. Each of the pixels 202 has an aspect ratio of 3:1,and includes three sub-pixels of red (R), green (G), and blue (B) thatare arranged vertically. The stereoscopic display monitor illustrated inFIG. 3 converts nine-parallax images consisting of nine images into anintermediate image in a given format (e.g., a grid-like format), andoutputs the result onto the display screen 200. In other words, thestereoscopic display monitor illustrated in FIG. 3 assigns and outputsnine pixels located at the same position in the nine-parallax images tothe pixels 202 arranged in nine columns. The pixels 202 arranged in ninecolumns function as a unit pixel group 203 that displays nine imagesfrom different viewpoint positions at the same time.

The nine-parallax images simultaneously output as the unit pixel group203 onto the display screen 200 are emitted with a light emitting diode(LED) backlight, for example, as parallel rays, and travel further inmultiple directions through the vertical lenticular sheet 201. Light foreach of the pixels included in the nine-parallax images is output inmultiple directions, whereby the light entering the right eye and theleft eye of the observer changes as the position (viewpoint position) ofthe observer changes. In other words, depending on the angle from whichthe observer perceives, the parallax image entering the right eye andthe parallax image entering the left eye are at different parallaxangles. Therefore, the observer can perceive a captured objectstereoscopically from any one of the nine positions illustrated in FIG.3, for example. At the position “5” illustrated in FIG. 3, the observercan perceive the captured object stereoscopically as the object facesdirectly the observer. At each of the positions other than the position“5” illustrated in FIG. 3, the observer can perceive the captured objectstereoscopically with its orientation changed. The stereoscopic displaymonitor illustrated in FIG. 3 is merely an example. The stereoscopicdisplay monitor for displaying nine-parallax images may be a liquidcrystal display with horizontal stripes of “RRR . . . , GGG . . . , BBB. . . ” as illustrated in FIG. 3, or a liquid crystal display withvertical stripes of “RGBRGB . . . ”. The stereoscopic display monitorillustrated in FIG. 3 may be a monitor using a vertical lens in whichthe lenticular sheet is arranged vertically as illustrated in FIG. 3, ora monitor using a diagonal lens in which the lenticular sheet isarranged diagonally.

Referring back to FIG. 1, the main apparatus 100 is an apparatus forgenerating an ultrasound image based on the reflection waves received bythe ultrasound probe 11, and includes the transmitter-receiver 110, aB-mode processor 120, a Doppler processor 130, an image generator 140,an image memory 150, an internal storage 160, and a controller 170, asillustrated in FIG. 1.

The transmitter-receiver 110 includes a trigger generator circuit, adelay circuit, a pulsar circuit, and the like, and supplies a drivingsignal to the ultrasound probe 11. The pulsar circuit generates a ratepulse for generating ultrasonic waves to be transmitted, repeatedly at agiven rate frequency. The delay circuit adds a delay time correspondingto each of the piezoelectric vibrators to each of the rate pulsesgenerated by the pulsar circuit. Such a delay time is required fordetermining the transmission directivity by converging the ultrasonicwaves generated in the ultrasound probe 11 into a beam. The triggergenerator circuit applies the driving signal (driving pulse) to theultrasound probe 11 at a timing based on the rate pulse. In other words,by causing the delay circuit to change the delay time to be added toeach of the rate pulses, the direction in which the ultrasonic waves aretransmitted from each piezoelectric vibrator surface is adjusted to agiven direction.

The transmitter-receiver 110 also includes an amplifier circuit, ananalog-to-digital (A/D) converter, and an adder, and generatesreflection wave data by applying various processes to the reflectionwave signal received by the ultrasound probe 11. The amplifier circuitamplifies the reflection wave signal on each channel, and performs again correction. The A/D converter performs an A/D conversion on thereflection wave signal having gain corrected, and adds a delay timerequired for determining a reception directivity. The adder performs anaddition on the reflection wave signal processed by the A/D converter,and generates the reflection wave data. Through the addition performedby the adder, a reflection component in the direction corresponding tothe reception directivity of the reflection wave signal is emphasized.

In the manner described above, the transmitter-receiver 110 controls thetransmission directivity and the reception directivity of the ultrasonicwave transmissions and receptions. The transmitter-receiver 110 has afunction for enabling delay information, a transmission frequency, atransmit driving voltage, and a numerical aperture, for example, to bechanged instantaneously under control performed by the controller 170 tobe described later. In particular, a change in the transmission drivingvoltage is performed by a linearly amplifying oscillation circuit thatis cable of switching values instantaneously, or a mechanism forelectrically switching a plurality of power units. Thetransmitter-receiver 110 is also capable of transmitting and receiving adifferent waveform for every frame or every rate.

The B-mode processor 120 receives the reflection wave data that is aprocessed reflection wave signal applied with the gain correction, theA/D conversion, and the addition by the transmitter-receiver 110, andperforms a logarithmic amplification, an envelope detection, and thelike, to generate data in which signal intensity is represented as abrightness level (B-mode data).

The B-mode processor 120 can change the bandwidth of frequencies to bevisualized by changing a detecting frequency. The B-mode processor 120is capable of performing parallel detections on a single piece ofreceived data, using two detecting frequencies.

From a single piece of data received from a region of interest in thesubject P to which an ultrasound contrast agent is injected, reflectionwave data resulted from the ultrasound contrast agent (microbubbles,bubbles) flowing through the region of interest can be separated fromreflection wave data resulted from the tissues in the region ofinterest, by using the function of the B-mode processor 120, and theimage generator 140 to be described later can generate a contrast imagein which the flowing bubbles are visualized highly sensitively, and ahistological image in which tissues are visualized in a manner allowingtheir forms to be observed.

The Doppler processor 130 frequency-analyzes velocity information in thereflection wave data received from the transmitter-receiver 110, andextracts blood flows, tissues, and contrast agent echo componentsresulted from the Doppler shift, and generates data (Doppler data) thatis moving body information such as average velocity, turbulence, power,and the like extracted for a plurality of points.

More specifically, the Doppler processor 130 is a processor being cableof performing tissue Doppler imaging (TDI) and color Doppler imaging(CDI). In other words, the Doppler processor 130 is a processor thatacquires movement information of tissues in a scanned area (tissuemovement information), and generates tissue Doppler data that is usedfor generating a tissue Doppler image, which indicates behaviors of thetissues. The Doppler processor 130 is also a processor that acquiresmovement information of blood flows existing in a scanned area (bloodflow movement information), and generates color Doppler data that isused for generating a color Doppler image, which indicates behaviors ofthe blood flows.

The B-mode processor 120 and the Doppler processor 130 according to thefirst embodiment are capable of processing both two-dimensionalreflection wave data and three-dimensional reflection wave data. Inother words, the B-mode processor 120 according to the first embodimentis capable of generating three-dimensional B-mode data fromthree-dimensional reflection wave data. The Doppler processor 130according to the first embodiment is capable of generatingthree-dimensional Doppler data from three-dimensional reflection wavedata.

The image generator 140 generates ultrasound images from the datagenerated by the B-mode processor 120 and the Doppler processor 130. Inother words, the image generator 140 generates a B-mode image in whichthe intensity of a reflection wave is represented as a luminance fromthe B-mode data generated by the B-mode processor 120. The imagegenerator 140 is also capable of generating a three-dimensional B-modeimage from the three-dimensional B-mode data generated by the B-modeprocessor 120.

The image generator 140 generates an average velocity image, aturbulence image, or a power image representing the moving bodyinformation or a color Doppler image being a combination of theseimages, from the Doppler data generated by the Doppler processor 130.The image generator 140 is also cable of generating a three-dimensionalcolor Doppler image from the three-dimensional Doppler data generated bythe Doppler processor 130.

Generally, the image generator 140 converts rows of scan line signalsfrom an ultrasound scan into rows of scan line signals in a videoformat, typically one used for television (performs a scan conversion),to generate an ultrasound image being an image to be displayed.Specifically, the image generator 140 generates an ultrasound image asan image to be displayed by performing a coordinate conversion inaccordance with the way ultrasound scan is performed with the ultrasoundprobe 11. In addition to the scan conversion, the image generator 140performs various image processes using, for example, a plurality ofimage frames applied with the scan conversion, such as an image processfor re-generating an image with averaged luminance (smoothing process)and an image process performed in the image with a differential filter(edge enhancement process).

The image generator 140 is capable of generating various images fordisplaying the volume data onto the monitor 13. Specifically, the imagegenerator 140 is capable of generating a multi-planar reconstruction(MPR) image or a rendering image (volume rendering image or surfacerendering image) from the volume data. Volume data herein includes athree-dimensional B-mode image, a three-dimensional color Doppler image,or virtual volume data plotted in a virtual three-dimensional space.

An example of a process of generating a volume rendering image performedby the image generator 140 will now be explained. FIG. 4 is a schematicfor explaining an example of the volume rendering process performed bythe image generator 140 according to the first embodiment. For example,it is assumed herein that the image generator 140 receives parallelprojection as a rendering condition, and a reference viewpoint position(5) and a parallax angle of “one degree”, as illustrated in the“nine-parallax image generating method (1)” in FIG. 4. In such a case,the image generator 140 generates nine parallax images, each having aparallax angle (angle between the lines of sight) shifted by one degree,by parallel projection, by moving the position of the viewpoint from (1)to (9) in such a way that the parallax angles are set in every “onedegree”. Before performing the parallel projection, the image generator140 establishes a light source radiating parallel light rays from theinfinity along the line of sight.

It is assumed now that the image generator 140 receives perspectiveprojection as a rendering condition, and a reference viewpoint position(5) and a parallax angle of “one degree”, as illustrated in the“nine-parallax image generating method (2)” in FIG. 4. In such a case,the image generator 140 generates nine parallax images, each having aparallax angle shifted by one degree, by perspective projection, bymoving the position of the viewpoint from (1) to (9) around the center(the center of gravity) of the volume data in such a way that theparallax angle is set in every “one degree”. Before performing theperspective projection, the image generator 140 establishes a pointlight source or a surface light source radiating lightthree-dimensionally about the line of sight, for each of the viewpoints.Alternatively, when the perspective projection is to be performed, theviewpoints (1) to (9) may be shifted in parallel depending on renderingconditions. The line of sight is laid in a direction extending from theviewpoint to the center (the center of gravity) of a cross-sectionalsurface of the volume data, as illustrated in FIG. 4.

The image generator 140 may also perform a volume rendering processusing both parallel projection and perspective projection, byestablishing a light source radiating light two-dimensionally, radiallyfrom a center on the line of sight for the vertical direction of thevolume rendering image to be displayed, and radiating parallel lightrays from the infinity along the line of sight for the horizontaldirection of the volume rendering image to be displayed.

The parallax image group generated by the image generator 140 is storedin the image memory 150. The ultrasonic diagnostic apparatus 1 thenconverts the parallax image group into an intermediate image in whichthe parallax image group is arranged in a predetermined format (e.g., agrid-like format), for example, and displays the image onto thestereoscopic display monitor. In this manner, the stereoscopic image canbe presented to physicians and ultrasonographers who are users.

Referring back to FIG. 1, the image memory 150 stores therein raw data(B-mode data and Doppler data) generated by the B-mode processor 120 andthe Doppler processor 130 and an ultrasound image to be displayedgenerated by the image generator 140, and virtual volume data generatedunder the control of the controller 170, which is to be described later.The virtual volume data will be explained later in detail. The imagememory 150 also stores therein output signal (radio frequency (RF))immediately after being processed by the transmitter-receiver 110, aluminance signal of an image, and various raw data as necessary.

The internal storage 160 stores therein control programs fortransmitting and receiving ultrasonic waves, performing the imageprocesses and a displaying process, and various data such as diagnosticinformation (e.g., a patient identification (ID) and observations by aphysician), and diagnostic protocols. The internal storage 160 is alsoused to store therein the image stored in the image memory 150 asrequired.

The controller 170 controls the overall process performed in theultrasonic diagnostic apparatus 1. Specifically, the controller 170controls the processes performed by the transmitter-receiver 110, theB-mode processor 120, the Doppler processor 130, and the image generator140, and controls to display an ultrasound image stored in the imagememory 150 onto the monitor 13 based on various setting requests inputby the operator via the input device 12, or various control programs andvarious setting information read from the internal storage 160.

The overall configuration of the ultrasonic diagnostic apparatus 1according to the first embodiment is as explained above. The ultrasonicdiagnostic apparatus 1 according to the first embodiment having such aconfiguration is configured to improve image visibility under thecontrol performed by the controller 170 to be explained below in detail.

Explained now is an example in which the image visibility is degraded inan examination conducted with an ultrasonic diagnostic apparatus. FIG. 5is a schematic for explaining an example of an issue to be addressed inthe first embodiment. FIG. 5 depicts how an intracardiac blood flow isdisplayed in a CDI. In other words, the image of the intracardiac bloodflow illustrated in FIG. 5 is an image on which a color Doppler image ofa reverse blood flow 50 and a normal blood flow 51 is superimposed overa B-mode image of a heart. Illustrated in FIG. 5 is velocity(V)—turbulence (variance) (T) representation that allows the reverseblood flow 50 to be observed, taking advantage of the fact that thereverse blood flow 50 has a higher turbulence than that of the normalblood flow 51. In the V-T representation, for example, when there is areverse blood flow, as illustrated in FIG. 5, the reverse blood flow 50is displayed in a different color than that of the normal blood flow 51.

At this time, if a representation time for the reverse blood flow 50illustrated in FIG. 5 is short, or the reverse blood flow 50 istemporally and spatially overlapped with the normal blood flow 51 or anartifact, for example, observations of the reverse blood flow 50 becomedifficult. In other words, the visibility of the image is degraded, andas a result, diagnostic accuracy or the throughput might be reduced.

Described now are some more examples of degraded image visibility otherthan that described above. For example, in an ultrasound contrastexamination using a contrast agent, echo signals from the contrast agentare displayed in an emphasized manner, while echo signals from thetissues are suppressed. In such a case, image visibility could degradebecause signals resulted from the tissues might be included in harmonicsor subharmonics that are echo signals from the contrast agent.Furthermore, when a coronary blood flow is observed using a CDI, theimage visibility could be degraded by clutter artifacts that aregenerated by the movement of myocardia (artifacts in which tissueDoppler signals are mixed).

Therefore, an object of the present application is to improve the imagevisibility in situations such as those explained above. The controller170 for executing control for improving the image visibility will be nowexplained in detail.

FIG. 6 is a schematic of an example of a configuration of the controller170 according to the first embodiment. As illustrated in FIG. 6, thecontroller 170 includes a separator 171, an image generation controller172, a display controller 173, and a depth setting module 174.

The separator 171 separates an arbitrary region of a displayed objectrepresented from image data, in a depth direction, based on acharacterizing quantity included in the image data. Specifically, theseparator 171 extracts a region represented from image data including acharacterizing quantity within a range specified by a given threshold,as an arbitrary region of a displayed object. As the characterizingquantity, the separator 171 uses at least one of velocity information,turbulence information, and power information acquired through the colorDoppler method. The image data represents velocity-related information,and the separator 171 separates a region by using turbulence as acharacterizing quantity so that a region with a higher turbulence isarranged closer to the viewer. The separator 171 also uses luminanceinformation as a characterizing quantity. Used in the first embodimentis an example in which turbulence information acquired by the colorDoppler method is used.

FIGS. 7A and 7B are schematics for explaining an example of a processperformed by the separator 171 according to the first embodiment. FIGS.7A and 7B illustrate an example in which the turbulence in the CDI datafor the intracardiac blood flow illustrated in FIG. 5 is used. Forexample, the separator 171 separates a target region of the intracardiacblood flow in the depth direction using the turbulence indicated by thearrow in FIG. 7A.

To explain with an example, to begin with, the separator 171 separatesturbulence ranging from “a to b” into two sections “a to c” and “c tob”, using a threshold “c”, as illustrated in FIG. 7B. The separator 171then separates a group of pixels representing the intracardiac bloodflow into two groups of pixels based on the turbulence. For example, theseparator 171 separates a group of pixels representing the intracardiacblood flow into a region representing the normal blood flow 51, whichhas a turbulence within the range “a-c”, and a region representing thereverse blood flow 50, which has a turbulence within the range “c-b”, asillustrated in FIG. 7B. The threshold may be specified by the operatorin advance, or each system may be provided with a unique threshold. Thethreshold may also be set automatically based on the turbulenceacquired. Furthermore, the threshold may also be selected from aplurality of preset alternatives depending on a situation (e.g.,depending on a displayed object, or a characterizing quantity beingused). A region in the B-mode image for which no CDI data is collected(e.g., cardiac valve or cardiac wall) may be excluded from theseparation, or separated by setting “zero” to the characterizingquantity (turbulence in the example explained above) of the region.Alternatively, the separator 171 may determine whether such a region isseparated depending on a situation (e.g., depending on a displayedobject, or a characterizing quantity being used).

Referring back to FIG. 6, the image generation controller 172 generatesan image to be displayed in which depth direction information isreflected on an arbitrary region of the displayed object, separated bythe separator 171. Specifically, the image generation controller 172causes the image generator 140 to generate virtual volume data in whichtwo-dimensional images representing regions separated by the separator171 are arranged in the depth direction within a virtual space based onthe turbulence. The image generation controller 172 then causes theimage generator 140 to generate a parallax image group to be displayedby causing the image generator 140 to apply a volume rendering processto the virtual volume data thus generated while changing the viewpointby the parallax number from a given direction.

FIG. 8 is a schematic for explaining an example of a process performedby the image generation controller 172 according to the firstembodiment. For example, the image generation controller 172 places thetwo-dimensional images representing the reverse blood flow 50 and thetwo-dimensional image representing the normal blood flow 51, both ofwhich are separated by the separator 171, in a depth direction set inadvance based on the turbulence, as illustrated as (A) in FIG. 8. Inother words, as illustrated as (A) in FIG. 8, the image generationcontroller 172 places the two-dimensional image representing the normalblood flow 51 in front of the two-dimensional image that is a B-modeimage representing the heart, and places the two-dimensional imagerepresenting the reverse blood flow 50 in front of the two-dimensionalimage representing the normal blood flow 51. In other words, the imagegeneration controller 172 places the two-dimensional images separated bythe separator 171 in such a way that a region with a higher turbulenceis arranged closer to the viewer, exactly in the manner separated by theseparator 171 in a virtual space.

The image generation controller 172 causes the image generator 140 togenerate virtual volume data in which the two-dimensional imagerepresenting the reverse blood flow 50, the two-dimensional imagerepresenting the normal blood flow 51, and the two-dimensional imagerepresenting the heart are arranged sequentially in the depth directionin the virtual space, as illustrated as (B) in FIG. 8. The imagegeneration controller 172 then causes the image generator 140 togenerate a parallax image group to be displayed by executing the volumerendering process from the direction of arrow 300, illustrated in FIG.8, based on the parallax number, for example. An interval between thetwo-dimensional images in the depth direction, the line of sight used inexecuting the volume rendering process, the parallax angle, and the likemay be specified to given values by the operator, or each system may beprovided with unique settings. Alternatively, these values may be setautomatically based on the turbulence acquired. Furthermore, theinterval between the two-dimensional images in the depth direction, theline of sight used in executing the volume rendering process, theparallax angle, and the like may also be selected from a plurality ofpreset alternatives depending on a situation (e.g., depending on adisplayed object, or a characterizing quantity being used).

Referring back to FIG. 6, the display controller 173 causes the monitor13 to display the parallax image group generated under the control ofthe image generation controller 172. For example, the display controller173 causes the monitor 13 to display the parallax image group generatedby applying the volume rendering process to the virtual volume dataillustrated in (B) in FIG. 8, with nine viewpoints from the directionindicated by the arrow 300.

As described above, in the ultrasonic diagnostic apparatus 1 accordingto the first embodiment, the image visibility is improved by presentinga stereoscopic image providing stereoscopic view of a region of interestto the operator.

Referring back to FIG. 6, the depth setting module 174 sets depthdirection information included in the image to be displayed generated bythe image generator, based on an operation of the operator.Specifically, when the operator makes an input operation via the inputdevice 12 while observing the stereoscopic image displayed on themonitor 13, the depth setting module 174 changes the depth of thestereoscopic image based on the operation. In other words, the depthsetting module 174 displays the stereoscopic image in a changed depth,by causing the image generator 140 to generate a parallax image groupafter increasing or reducing the depth-direction interval between thetwo-dimensional images arranged in the virtual volume data from whichthe stereoscopic image currently being displayed is generated, and bycausing the monitor 13 to display the parallax image group.

FIG. 9 is a schematic for explaining an example process performed by thedepth setting module 174 according to the first embodiment. FIG. 9illustrates an example in which a corresponding relationship between thedepth and the turbulence is in a proportional relationship. For example,the depth setting module 174 causes the monitor 13 to display a graphindicating the relationship between the depth and the turbulence, asillustrated in FIG. 9. The depth setting module 174 then changes thedepth of the stereoscopic image based on an inclination of a line 301changed by the operator via the input device 12.

To explain using an example, to emphasize the feel of depth, theoperator changes the inclination of the line 301 illustrated in (A) inFIG. 9 to the inclination of the line 301 illustrated in (B) in FIG. 9.The depth setting module 174 then displays a stereoscopic image having alarger depth by increasing the depth-direction interval between thetwo-dimensional images arranged in the virtual volume data from whichthe stereoscopic image currently being displayed is generated, based ona change in the inclination, causing the image generator 140 to generatea parallax image group, and causing the monitor 13 to display theparallax image group. By contrast, to suppress the feel of depth, theoperator changes the inclination of the line 301 illustrated in (B) inFIG. 9 to the inclination of the line 301 illustrated in (A) in FIG. 9,for example.

As described above, the ultrasonic diagnostic apparatus 1 according tothe first embodiment can also receive a depth setting performed by theoperator, whereby images further improved in visibility can be provided.

Explained in the first embodiment is an example in which the turbulencein the CDI is used; however, the displayed object can also be separatedinto target regions by using velocity or power in the CDI data generatedby the Doppler processor 130, or luminance included in the B-mode datagenerated by the B-mode processor 120.

A process performed by the ultrasonic diagnostic apparatus 1 accordingto the first embodiment will now be explained with reference to FIG. 10.FIG. 10 is a flowchart illustrating the process performed by theultrasonic diagnostic apparatus 1 according to the first embodiment. Asillustrated in FIG. 10, in the ultrasonic diagnostic apparatus 1according to the first embodiment, if a visibility improvement mode isON (Yes at Step S101), the separator 171 acquires characterizingquantity information (for example, turbulence, velocity, power,luminance) (Step S102).

The separator 171 separates a displayed object based on thecharacterizing quantity thus acquired and a preset threshold (StepS103). The image generation controller 172 then sets a depth in whichthe two-dimensional images of the regions that are separated by theseparator 171 are arranged (Step S104), and generates the virtual volumedata (Step S105).

The image generation controller 172 then applies a rendering process tothe virtual volume data thus generated, based on the parallax number(Step S106). The display controller 173 then causes the monitor 13 todisplay a parallax image group generated under the control of the imagegeneration controller 172 (Step S107). The depth setting module 174 thendetermines if a depth change request for changing the depth has beenreceived (Step S108).

If a depth change request has been received (Yes at Step S108), thedepth setting module 174 returns to Step S104, and sets the depth of theimage. By contrast, if a depth change request has not been received (Noat Step S108), the ultrasonic diagnostic apparatus 1 according to thefirst embodiment ends the process.

As described above, according to the first embodiment, the separator 171separates an arbitrary region of a displayed object represented from theimage data, in a depth direction, based on a characterizing quantityincluded in the image data. The image generation controller 172generates an image to be displayed in which depth direction informationis reflected on the arbitrary region of the displayed object separatedby the separator 171. The display controller 173 displays the image tobe displayed generated by the image generation controller 172 onto themonitor 13 that is capable of providing a stereoscopic vision.Therefore, the ultrasonic diagnostic apparatus 1 according to the firstembodiment can provide a stereoscopic vision of a region of interest,and the image visibility can be improved. Furthermore, by improving theimage visibility, the ultrasonic diagnostic apparatus 1 according to thefirst embodiment can improve diagnostic accuracy and diagnosticthroughput.

Furthermore, according to the first embodiment, the separator 171 usesat least one of velocity information, turbulence information, and powerinformation acquired through the color Doppler method as thecharacterizing quantity. Therefore, when the reverse blood flow or thecoronary blood flow is to be observed, the ultrasonic diagnosticapparatus 1 according to the first embodiment enables the visibility ofeach of these regions to be specifically improved.

Furthermore, according to the first embodiment, the image datarepresents velocity-related information, and the separator 171 usesturbulence as a characterizing quantity, and performs separation so thata region with a higher turbulence is arranged closer to the viewer.Therefore, the ultrasonic diagnostic apparatus 1 according to the firstembodiment allows a region in which the observer is interested to bedisplayed closer to the viewer. Thus, the image visibility can befurther improved.

Furthermore, according to the first embodiment, the separator 171 usesluminance information as a characterizing quantity. Therefore, theultrasonic diagnostic apparatus 1 according to the first embodiment canimprove the visibility of a region of interest specifically, in anexamination using a contrast agent.

For example, in the contrast-echo method that allows a blood flowbehavior to be observed clearly by injecting microbubbles and the likeinto a vein as a contrast agent and amplifying the blood flow signal,the ultrasonic diagnostic apparatus 1 according to the first embodimentcan specifically improve the visibility of the blood flow behaviorrepresented in the contrast image, and can improve diagnostic accuracyand diagnostic throughput, such as differential diagnosis of a cancer ordiffuse liver disease diagnosis, such as chronic hepatitis andcirrhosis.

Furthermore, according to the first embodiment, the separator 171extracts a region represented from image data including a characterizingquantity within a range specified by a given threshold as an arbitraryregion of a displayed object. Therefore, the ultrasonic diagnosticapparatus 1 according to the first embodiment can display regions withclose characterizing quantities in the same depth, to enable the imagevisibility to be improved further.

For example, if a highly granular depth is established in a space basedon the characterizing quantity, regions located near to each other mightbe allocated to depths that are greatly different from each other. Toexplain using an example, turbulence might vary within the same reverseblood flow. Therefore, if such variation is reflected on the depth, thevisibility is degraded. The ultrasonic diagnostic apparatus 1 accordingto the first embodiment enables degradation of visibility caused byvariation in the characterizing quantity as explained above to beavoided.

Furthermore, according to the first embodiment, the depth setting module174 changes the depth direction information included in the image to bedisplayed generated by the image generation controller 172, based on anoperation of an operator. The image generation controller 172 thengenerates an image to be displayed on which the depth directioninformation set by the depth setting module 174 is reflected. Theultrasonic diagnostic apparatus 1 according to the first embodiment canalso receive a depth setting from the operator, whereby an image withhigher visibility can be provided.

Second Embodiment

While the first embodiment is described above, embodiments other thanthe first embodiment are still possible.

Explained in the first embodiment is an example in which a stereoscopicimage is generated and displayed by the ultrasonic diagnostic apparatus1. However, embodiments are not limited thereto, and may represent anexample in which a stereoscopic image is generated and displayed by animage processing apparatus, for example. In such an implementation, forexample, the image processing apparatus acquires B-mode image data andDoppler image data, separates regions of a displayed object based oncharacterizing quantities (velocity, turbulence, power, and luminance),and generates virtual volume data in which two-dimensional imagesrepresenting the regions thus separated are positioned at differentpositions in a depth direction within a virtual space. The imageprocessing apparatus then generates a parallax image group from thevirtual volume data thus generated based on the parallax number, anddisplays the parallax image group.

Furthermore, explained in the first embodiment is an example in whichtwo-dimensional B-mode image data and Doppler image data are used.However, embodiments are not limited thereto, and may represent anexample in which three-dimensional B-mode image data and Doppler imagedata are used. In such an example, an MPR image or a volume renderingimage generated from three-dimensional B-mode image data and Dopplerimage data are used as an initial image, and a stereoscopic image isgenerated based on the characterizing quantity in the initial image.

Furthermore, explained in the first embodiment is an example in whichregions of a displayed object are separated using a single threshold.However, embodiments are not limited thereto, and may also represent anexample in which two or more thresholds are used, for example.

Furthermore, explained in the first embodiment is an example in which athreshold separating the entire range of the characterizing quantity(turbulence) into two sections is used. However, embodiments are notlimited thereto, and may represent an example using a threshold allowinga region having a characterizing quantity within a specific range in theentire range of the characterizing quantity to be separated, forexample. For example, thresholds may be given to the turbulence “a-b”illustrated in FIG. 7B in such a way that “a<c1 to c2<c<d1 to d2<b”, andregions indicating a characterizing quantity within the range “c1 to c2”and the range “d1 to d2” may be separated.

Furthermore, explained in the first embodiment is an example in whichthe threshold is preset. However, embodiments are not limited thereto,and may represent an example in which the threshold is set automaticallyusing color Doppler image data. In such an example, for example, theturbulence included in the Doppler image data is expressed in a normaldistribution, and a threshold for separating a specific region isspecified.

Explained in the first embodiment is an example in which the depth ofthe stereoscopic image is changed by changing the interval at which thetwo-dimensional images are arranged in the virtual volume data. However,embodiments are not limited thereto, and may represent an example inwhich the depth of the stereoscopic image is changed by changing theparallax angle used in performing the volume rendering process, forexample.

Explained in the first embodiment is an example in which a singlecharacterizing quantity is used. However, embodiments are not limitedthereto, and may represent an example in which two or more differentcharacterizing quantities are used, for example.

As explained above, according to the first embodiment and the secondembodiment, image visibility can be improved.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. An ultrasonic diagnostic apparatus comprising: acontroller configured to separate color Doppler image data into aplurality of groups, wherein each group represents a region in an imagedobject, wherein separating the image data into a plurality of groupscomprises separating pixels included in the image data into theplurality of groups based on turbulence of each pixel included in theimage data and a given threshold, generate virtual volume data in whicheach of the plurality of groups comprises a two-dimensional imagearranged in a depth direction in a virtual space with groups having ahigher turbulence being arranged closer to a viewer, and generate astereoscopic image to be displayed in which each group in the virtualvolume is displayed stereoscopically at a position corresponding to theturbulence in the depth direction within the stereoscopic image, byapplying a volume rendering process to the virtual volume data; and adisplay configured to display the stereoscopic image.
 2. The ultrasonicdiagnostic apparatus according to claim 1, wherein the controller isconfigured to separate the pixels based on at least one of velocity andpower in addition to the turbulence.
 3. The ultrasonic diagnosticapparatus according to claim 2, wherein the controller is configured tofurther separate the pixels based on luminance information.
 4. Theultrasonic diagnostic apparatus according to claim 1, wherein thecontroller is configured to separate the pixels based on luminanceinformation in addition to the turbulence.
 5. The ultrasonic diagnosticapparatus according to claim 1, wherein the controller is configured toextract the groups comprising pixels with turbulence within a rangespecified by the given threshold.
 6. The ultrasonic diagnostic apparatusaccording to claim 1, wherein the controller is further configured tochange depth direction information associated with the stereoscopicimage to be displayed, based on an operation of an operator, andgenerate an updated stereoscopic image to be displayed on which thedepth direction information set is reflected.
 7. The ultrasonicdiagnostic apparatus according to claim 1, wherein the controller isfurther configured to separate the color Doppler image data byseparating pixels representing intracardiac blood flow into a firstgroup representing normal blood flow and a second group representingreverse blood flow, to generate second virtual volume data comprising atwo-dimensional image of the first group and a two-dimensional image ofthe second group, wherein the two-dimensional image of the second groupis arranged closer to the viewer in the depth direction than thetwo-dimensional image of the first group, and cause the display todisplay an image corresponding to the second virtual volume data.
 8. Theultrasonic diagnostic apparatus according to claim 1, wherein thecontroller is configured to automatically set the given threshold usingthe color Doppler image data.
 9. An image processing apparatuscomprising: a controller configured to separate color Doppler image datainto a plurality of groups, wherein each group represents a region in animaged object, wherein separating the image data into a plurality ofgroups comprises separating pixels included in the image data into theplurality of groups based on turbulence of each pixel included in theimage data and a given threshold, generate virtual volume data in whicheach of the plurality of groups comprises a two-dimensional imagearranged in a depth direction in a virtual space with groups having ahigher turbulence being arranged closer to a viewer, generate astereoscopic image to be displayed in which each group in the virtualvolume is displayed stereoscopically at a position corresponding to theturbulence in the depth direction within the stereoscopic image, byapplying a volume rendering process to the virtual volume data, andcause a display to display the stereoscopic image.
 10. A methodcomprising: separating, using a controller, color Doppler image datainto a plurality of groups, wherein each group represents a region in animaged object, wherein separating the image data into a plurality ofgroups comprises separating pixels included in the image data into theplurality of groups based on turbulence of each pixel included in theimage data and a given threshold; generating, using the controller,virtual volume data in which each of the plurality of groups comprises atwo-dimensional image arranged in a depth direction in a virtual spacewith groups having a higher turbulence being arranged closer to aviewer; generating, using the controller, a stereoscopic image to bedisplayed in which each group in the virtual volume is displayedstereoscopically at a position corresponding to the turbulence in thedepth direction within the stereoscopic image, by applying a volumerendering process to the virtual volume data; and causing a display todisplay the stereoscopic image.